PEX (cross-linked polyethylene) pipe is a flexible plastic tubing used primarily for hot and cold water distribution in residential HVAC and plumbing systems. PEX is manufactured through cross-linking polyethylene molecules, creating improved strength and flexibility compared to standard polyethylene. It resists freezing and can operate safely between 40°F and 200°F.
Technical Features
PEX tubing comes in 1/2-inch and 3/4-inch diameters for most HVAC applications. The material meets ASTM F876 standards for potable water use. PEX expands at 0.15 percent per 100 degrees Fahrenheit, requiring consideration in installation. It is oxygen-barrier or non-barrier depending on application requirements.
HVAC and Plumbing Use
PEX is ideal for radiant floor heating, snow melt systems, and water distribution loops. Its flexibility eliminates many fittings, reducing installation time and leak points. It works well in both new construction and retrofit applications.
Installation Advantages
PEX connects using crimp rings, compression fittings, or push-fit connectors without soldering or gluing. Installation labor costs are significantly lower than copper. However, PEX cannot be used for refrigerant lines in air conditioning systems, limiting its HVAC scope to water-based applications only.